In addition, CodY sensed the oligopeptide permease Ami to repress competence for genetic transformation in Streptococcus thermophilus, 21. CodY also regulates primary metabolism like carbon metabolism, iron uptake and biosynthesis of branched-chain amino acids in other bacterias including Streptococcus pneumonia 18, Streptococcus mutans 19, and Streptococcus thermophiles 20. In Bacillus subtilis, CodY regulates metabolic pathways and cellular processes, such as peptide and sugar uptake, branched-chain amino acid (BCAA) biosynthesis, the development of genetic competence and the regulation of cellular motility 17. suis also uses other regulators, such as CcpA 14 and Zur 15, to respond to changing environments.ĬodY is a global transcriptional regulator of gene expression in low G + C gram-positive bacteria 16. The TCS includes at least 15 components that have been predicted through bioinformatics analysis 13. suis uses the two-component system (TCS) as the common regulatory mechanism to response to environmental signals. suis 2 bacterial survival during pathogen-host interaction 12. Rgg as a global transcriptional regulator, promotes S. MRP can bind human fibrinogen (hFg) and the MRP-hFg interaction increases the permeability of the blood-brain barrier (BBB) through which regulating the development of S. Muramidase-released protein (MRP) is as an important virulence marker of S. suis is also associated with the pathogen-host interaction. suis capsule is a virulence factor because capsular mutants are nonpathogenic and are more rapidly cleared from the bloodstream than the wild-type strain 10. In murine and porcine infection models, the S. suis is associated with the polysaccharide capsule, which is rich in sialic acid and confers antiphagocytic properties on S. suis 2 have been published in recent years, our understanding of the pathogenesis and virulence factors remains very limited 9. suis infection have been reported in China, United States, Canada, New Zealand, Australia Korea and Greece 6, 7, 8.Īlthough many studies of S. Hitherto, there are many cases of human S. suis, especially serotype 2, also causes serious infections in humans who are in contact with infected swine or pork-derived products 3, 4 and can induce meningitis, septic shock and permanent hearing loss 4, 5. suis 2 is thought to be the most virulent and is the most frequently isolated in association with diseases in most countries 2. Based on the capsular polysaccharides, 33 serotypes (types 1 to 31, 33, and 1/2) have been identified 2. suis causes great economic losses to the swine industry worldwide each year and is responsible for a variety of diseases, including meningitis, septicemia, arthritis, pneumonia, and even death 1. suis) is a prevalent pathogen and an important zoonotic agent in swine. suis 2, and at least via regulating sialic acid synthesis and capsule thickness. ![]() Overall, mutation of codY modulated bacterial virulence by affecting the growth and colonization of S. Finally, the codY mutation altered the expressions of many virulence related genes, including sialic acid synthesis genes, leading to a decreased sialic acid content in capsule. suis 2 and changed the surface structures analylized by SDS-PAGE. Morphological analysis revealed that the codY mutation decreased the thickness of the capsule of S. The codY mutation also attenuated the virulence of S. The codY mutation led to decreased binding of the pathogen to the host cells, easier clearance by RAW264.7 macrophages and decreased growth ability in fresh blood of Cavia porcellus. The result showed that the codY mutation significantly inhibited cell growth, adherence and invasion ability of S. ![]() suis 2), a mutant codY clone named ∆codY was constructed to explore the phenotypic variation between ∆codY and the wild-type strain. To study the functions of CodY in Streptococcus suis serotype 2 ( S. The main role of CodY, a global regulatory protein in most low G + C gram-positive bacteria, is in transcriptional repression.
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